class Solution {
    int dx[4] = {0, 0, -1, 1};
    int dy[4] = {1, -1, 0, 0};
    int m, n;
    int prev;
 
public:
    vector<vector<int>> floodFill(vector<vector<int>>& image, int sr, int sc, int color) {
        prev = image[sr][sc];
        if(prev == color)
            return image;
        m = image.size(), n = image[0].size();
        dfs(image, sr, sc, color);
        return image;
    }
 
    void dfs(vector<vector<int>>& image, int sr, int sc, int color)
    {
        image[sr][sc] = color;
        for(int i = 0; i < 4; ++i)
        {
            int x = sr + dx[i], y = sc + dy[i];
            if(x >= 0 && x < m && y >= 0 && y < n && image[x][y] == prev)
            {
                dfs(image, x, y, color);
            }
        }
    }
};